Today Ethernet is the dominant computer networking technology. As Ethernet gains wide popularity among enterprise, carriers, and cloud service providers, energy consumption by Ethernet based systems becomes an important concern. In an Ethernet based system, the majority of Ethernet transmission channels spend significant time waiting for data packets. Worse, during idle periods, Ethernet transmission channels still consume power at near full active levels because of clock synchronization requirements during those idle periods.
Concerning power consumption of legacy Ethernet equipment, two important facts have been observed:
(a). Consumption increases with the transmission channel speed. This is due to the increased hardware complexity that is required to achieve higher speeds;
(b). Consumption is mostly maximum and does not necessarily depend on the traffic load because of the continuous transmission of physical layer signaling in the absence of user data. This signaling is mandatory to keep the receivers aligned to the channel conditions.
In order to address Ethernet power consumption issue, the Energy Efficient Ethernet (EEE), sometimes referred to as Green Ethernet, is proposed. EEE is a set of enhancements to the twisted-pair and backplane Ethernet family of networking stands that allow for less power consumption during period of low data activity. The intention is to reduce power consumption by 50% or more without impacting the vital function that these network interfaces perform in a communication infrastructure. For example, the Institute of Electrical and Electronics Engineers (IEEE), through the IEEE 802.3az task force, has developed a set of standards for the effort. Yet, the mechanism and standard proposed have deficiency in transmission efficiency that should be improved.